The present disclosure is related to a head up display apparatus for use in vehicles such as automobiles.
Conventionally, head up display apparatuses are known as an apparatus that displays directional commands, warnings, traveling speed, etc. to drivers of automobiles and the like. These head up display apparatuses project virtual images of images to be displayed onto image reflection surfaces of windshields or combiners, etc., to enable drivers to discriminate information necessary to drive automobiles or the like, without averting their eyes from fields of view.
It is possible to display virtual images of information which is preferably displayed in the forward field of view of a driver from among information to be displayed by such a head up display apparatus, such as directional commands, warnings, etc., at greater distances from an image reflection surface. Thereby, movement of the line of sight and/or the focal point of the driver's eyes can be suppressed.
Inversely, it is possible to suppress movement of the line of sight and/or the focal point of the driver's eyes by displaying virtual images of information which is preferably displayed in the vicinity of the console of an automobile, such as traveling speed, at closer distances from the image reflection surface.
For this reason, Japanese Unexamined Patent Publication No. 2012-179935 and Japanese Patent No. 4816605 propose head up display apparatuses which are capable of displaying virtual images at a plurality of positions at different distances from an image reflection surface.